US4537050A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of controlling a stand for rolling strip material
Assignee: British Aluminum Co Ltd
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Filing: 1984-11-08
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Granted: 1985-08-27
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Expires: 2004-11-08
Abstract
Abstract A method of controlling one stand of a mill for rolling strip material, the mill having upper and lower back-up rolls and a pair of work rolls disposed between the back-up rolls, first and second screw means for respectively controlling movement of the ends of one of the back-up rolls and first and second jack means for respectively applying forces to each of the ends of the work rolls and a shape sensor having outputs from which the stress distribution across the width of the rolled strip is determined, comprising analyzing the effect upon the shape of the strip of the operation of the screw means and the jack means and deriving mathematical expressions, each including a control parameter, respectively representative of such operations determining the difference between said stress distribution and a desired stress distribution and obtaining a correction of stress distribution characterized by separately analyzing the effect upon the shape of the strip of the operation of each screw means and each jack means and deriving four mathematical expressions each including a control parameter respectively representative of such operations, determining a single error distribution E (x) as the difference between said stress distribution and a desired stress distribution, obtaining a single correction of stress distribution C (x) by determining an optimum value for each of said control parameters such that a functional of the distribution E (x)-C (x) is minimized and separately controlling each of said screws and jacks in accordance with said control parameters.
Inventors
- 👤 Greyham F. Bryant
- 👤 Peter D. Spooner
- 👤 William K. J. Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 01:31
CPC Classifications
B; B21; B21B; B21B37/00; B21B37/28; B21B37/38; B21B37/30; B21B37/32
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
248 words
A method of controlling one stand of a mill for rolling strip material, the mill having upper and lower back-up rolls and a pair of work rolls disposed between the back-up rolls, first and second screw means for respectively controlling movement of the ends of one of the back-up rolls and first and second jack means for respectively applying forces to each of the ends of the work rolls and a shape sensor having outputs from which the stress distribution across the width of the rolled strip is determined, comprising determining the effect upon the shape of the strip of the joint operation of the screw means and the joint operation of the jack means and deriving two mathematical expressions, respectively, representative of such operations, determining the difference between said stress distribution and a desired stress distribution and obtaining a correction of stress distribution characterised by separately determining the effect upon the shape of the strip of the operation of each screw means and each jack means and deriving four mathematical expressions each including a control parameter respectively representative of such operations, determining a single error distribution E (x) as the difference between said stress distribution and a desired stress distribution, obtaining a single correction of stress distribution C (x) by determining an optimum value for each of said control parameters such that a function of the distribution E (x)-C (x) is minimized and separately controlling each of said screws and jacks in accordance with said control parameters.
Claim 2
Independent Claim
248 words
A method of controlling one stand of a mill for rolling strip material, the mill having upper and lower back-up rolls and a pair of work rolls disposed between the back-up rolls, first and second screw means for respectively controlling movement of the ends of one of the back-up rolls and first and second jack means for respectively applying forces to each of the ends of the work rolls and a shape sensor having outputs from which the stress distribution across the width of the rolled strip is determined, comprising determining the effect upon the shape of the strip of the joint operation of the screw means and the joint operation of the jack means and deriving two mathematical expressions, respectively, representative of such operations, determining the difference between said stress distribution and a desired stress distribution and obtaining a correction of stress distribution characterised by separately determining the effect upon the shape of the strip of the operation of each screw means and each jack means and deriving four mathematical expressions each including a control parameter respectively representative of such operations, determining a single error distribution E (x) as the difference between said stress distribution and a desired stress distribution, obtaining a single correction of stress distribution C (x) by determining an optimum value for each of said control parameters such that a function of the distribution E (x)-C (x) is minimized and separately controlling each of said screws and jacks in accordance with said control parameters.
Claim 3
Dependent Claim
54 words
A method according to claim 1 in which the distribution C (x) is obtained so that the expression E (x)-C (x) is minimized without affecting strip thickness at some predetermined position across the strip width so as to ensure non-interaction between the shape control and any gauge control mechanism associated with the mill stand.
Claim 4
Dependent Claim
18 words
A method according to claim 2 in which the predetermined position is the centre line of the strip.
Claim 5
Dependent Claim
27 words
A method according to claim 2 in which C (x) is determined so that the strip thickness at a predetermined position across the strip width is altered.
Claim 6
Dependent Claim
164 words
A method according to claim 1 in which the stress distribution left in the strip after applying primary stress correction control to the screws and jacks is further reduced by separately modifying the thermal profile of the rolls in a multiplicity of zones disposed along the roll and respectively corresponding to selected output channels or groups of output channels of the shape sensor the modification in each zone extending over a predetermined area of the rolls comprising calculating an influence factor for each zone depending upon the extent and magnitude of the influence of the modification of each zone on the predetermined areas associated with adjoining zones, effecting said modification of selected zones corresponding with those channels of the shape sensor the output of which represents uncorrected stress in the strip the magnitude and sense of the modification is selected zones being subject to said influence factor to vary the thermal profile of the rolls in the sense to minimize said remaining stress distribution.
Claim 7
Dependent Claim
53 words
A method according to claim 5 in which said modification is by coolant sprays and the flow of coolant in each spray zone is varied to minimize in a Least Squares sense the distribution E (x)-D (x) where D (x) is derived by adding the effects of the influence functions from individual zones.
Claim 8
Dependent Claim
164 words
A method according to claim 2 in which the stress distribution left in the strip after applying primary stress correction control to the screws and jacks is further reduced by separately modifying the thermal profile of the rolls in a multiplicity of zones disposed along the roll and respectively corresponding to selected output channels or groups of output channels of the shape sensor the modification in each zone extending over a predetermined area of the rolls comprising calculating an influence factor for each zone depending upon the extent and magnitude of the influence of the modification of each zone on the predetermined areas associated with adjoining zones, effecting said modification of selected zones corresponding with those channels of the shape sensor the output of which represents uncorrected stress in the strip the magnitude and sense of the modification in selected zones being subject to said influence factor to vary the thermal profile of the rolls in the sense to minimize said remaining stress distribution.
Claim 9
Dependent Claim
53 words
A method according to claim 7 in which said modification is by coolant sprays and the flow of coolant in each spray zone is varied to minimize in a Least Squares sense the distribution E (x)-D (x) where D (x) is derived by adding the effects of the influence functions from individual zones.
Claim 10
Dependent Claim
164 words
A method according to claim 3 in which the stress distribution left in the strip after applying primary stress correction control to the screws and jacks is further reduced by separately modifying the thermal profile of the rolls in a multiplicity of zones disposed along the roll and respectively corresponding to selected output channels or groups of output channels of the shape sensor the modification in each zone extending over a predetermined area of the rolls comprising calculating an influence factor for each zone depending upon the extent and magnitude of the influence of the modification of each zone on the predetermined areas associated with adjoining zones, effecting said modification of selected zones corresponding with those channels of the shape sensor the output of which represents uncorrected stress in the strip the magnitude and sense of the modification in selected zones being subject to said influence factor to vary the thermal profile of the rolls in the sense to minimize said remaining stress distribution.
Claim 11
Dependent Claim
53 words
A method according to claim 9 in which said modification is by coolant sprays and the flow of coolant in each spray zone is varied to minimize in a Least Squares sense the distribution E (x)-D (x) where D (x) is derived by adding the effects of the influence functions from individual zones.
Claim 12
Dependent Claim
164 words
A method according to claim 4 in which the stress distribution left in the strip after applying primary stress correction control to the screws and jacks is further reduced by separately modifying the thermal profile of the rolls in a multiplicity of zones disposed along the roll and respectively corresponding to selected output channels or groups of output channels of the shape sensor the modification in each zone extending over a predetermined area of the rolls comprising calculating an influence factor for each zone depending upon the extent and magnitude of the influence of the modification of each zone on the predetermined areas associated with adjoining zones, effecting said modification of selected zones corresponding with those channels of the shape sensor the output of which represents uncorrected stress in the strip the magnitude and sense of the modification in selected zones being subject to said influence factor to vary the thermal profile of the rolls in the sense to minimize said remaining stress distribution.
Claim 13
Dependent Claim
53 words
A method according to claim 11 in which said modification is by coolant sprays and the flow of coolant in each spray zone is varied to minimize in a Least Squares sense the distribution E (x)-D (x) where D (x) is derived by adding the effects of the influence functions from individual zones.
References Cited (Backward Citations)
US1380250A
Cited
GB899532A
Cited
GB1160112A
Cited
US3518858A
Cited
US3802237A
Cited
GB1587420A
Cited
GB2012198A
Cited
GB2017974A
Cited
US4262511A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-08-26 | 1989-02-25 | 1989-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-26 | 1993-02-25 | 1993-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-26 | 1997-02-25 | 1997-08-27 | $7700.00 | Window Closed / Lapsed |